1. Field of the Invention
The present inventions relate to assemblies that utilize laser energy to provide electrical, mechanical or electro-mechanical energy for use in apparatuses, and in particular apparatuses that operate in remote, hostile, extreme or difficult to access locations, such as, subsea equipment, mining equipment, drilling equipment, flow control equipment, plugging and abandonment equipment and nuclear remediation equipment. The present inventions relate to laser apparatus that may perform laser cutting operations, cleaning operations, or other types of laser operations, as well as, potentially other non-laser operations; and which apparatus may also have assemblies that utilize laser energy to provide electrical, mechanical or electro-mechanical energy. By way of illustration the present inventions embrace subsea equipment that utilize tethers, such as subsea vehicles, remotely operated vehicles (“ROV”s), subsea tractors, subsea trenchers, and subsea excavation tools. Thus, and in particular, the present inventions relate to novel subsea vehicles that utilize high power laser energy, including high power laser cables and tethers. The present inventions further relate to subsea laser tools that can be used with an ROV or as a stand-alone tool. These tools deliver high power laser beams to cut, clean, remove material, and perform other tasks that may be accomplished by high power laser energy. These tools and related apparatus and systems bring high power laser technology to the seafloor, subsea environment, and equipment and structures located below the surface of the water; as well as, to other extreme or difficult to access environments or locations, such as within a borehole, a mine, or a nuclear facility.
As used herein, unless specified otherwise the terms “blowout preventer,” “BOP,” and “BOP stack” are to be given their broadest possible meaning, and include: (i) devices positioned at or near the borehole surface, e.g., the seafloor, which are used to contain or manage pressures or flows associated with a borehole; (ii) devices for containing or managing pressures or flows in a borehole that are associated with a subsea riser; (iii) devices having any number and combination of gates, valves or elastomeric packers for controlling or managing borehole pressures or flows; (iv) a subsea BOP stack, which stack could contain, for example, ram shears, pipe rams, blind rams and annular preventers; and, (v) other such similar combinations and assemblies of flow and pressure management devices to control borehole pressures, flows or both and, in particular, to control or manage emergency flow or pressure situations.
As used herein, unless specified otherwise “offshore” and “offshore drilling activities”, “offshore activities” and similar such terms are used in their broadest sense and would include activities on, or in, any body of water, whether fresh or salt water, whether manmade or naturally occurring, such as for example rivers, lakes, canals, inland seas, oceans, seas, bays and gulfs, such as the Gulf of Mexico. As used herein, unless specified otherwise the term “offshore drilling rig” is to be given its broadest possible meaning and would include fixed towers, tenders, platforms, barges, jack-ups, floating platforms, drill ships, dynamically positioned drill ships, semi-submersibles and dynamically positioned semi-submersibles. As used herein, unless specified otherwise the term “seafloor” is to be given its broadest possible meaning and would include any surface of the earth that lies under, or is at the bottom of, any body of water, whether fresh or salt water, whether manmade or naturally occurring. As used herein, unless specified otherwise the terms “well” and “borehole” are to be given their broadest possible meaning and include any hole that is bored or otherwise made into the earth's surface, e.g., the seafloor or sea bed, and would further include exploratory, production, abandoned, reentered, reworked, and injection wells.
As used herein, unless specified otherwise the term “fixed platform,” would include any structure that has at least a portion of its weight supported by the seafloor. Fixed platforms would include structures such as: free-standing caissons, well-protector jackets, pylons, braced caissons, piled-jackets, skirted piled-jackets, compliant towers, gravity structures, gravity based structures, skirted gravity structures, concrete gravity structures, concrete deep water structures and other combinations and variations of these. Fixed platforms extend from at or below the seafloor to and above the surface of the body of water, e.g., sea level. Deck structures are positioned above the surface of the body of water a top of vertical support members that extend down in to the water to the seafloor. Fixed platforms may have a single vertical support, or multiple vertical supports, e.g., pylons, legs, etc., such as a three, four, or more support members, which may be made from steel, such as large hollow tubular structures, concrete, such as concrete reinforced with metal such as rebar, and combinations of these. These vertical support members are joined together by horizontal and other support members. In a piled-jacket platform the jacket is a derrick like structure having hollow essentially vertical members near its bottom. Piles extend out from these hollow bottom members into the seabed to anchor the platform to the seabed.
The construction and configuration of fixed platforms can vary greatly depending upon several factors, including the intended use for the platform, load and weight requirements, seafloor conditions and geology, location and sea conditions, such as currents, storms, and wave heights. Various types of fixed platforms can be used over a great range of depths from a few feet to several thousands of feet. For example, they may be used in water depths that are very shallow, i.e., less than 50 feet, a few hundred feet, e.g., 100 to 300 feet, and a few thousand feet, e.g., up to about 3,000 feet or even greater depths may be obtained. These structures can be extremely complex and heavy, having a total assembled weight of more than 100,000 tons. They can extend many feet into the seafloor, as deep as 100 feet or more below the seafloor.
As used herein the term “drill pipe” is to be given its broadest possible meaning and includes all forms of pipe used for drilling activities; and refers to a single section or piece of pipe. As used herein the terms “stand of drill pipe,” “drill pipe stand,” “stand of pipe,” “stand” and similar type terms are to be given their broadest possible meaning and include two, three or four sections of drill pipe that have been connected. e.g., joined together, typically by joints having threaded connections. As used herein the terms “drill string,” “string,” “string of drill pipe,” “string of pipe” and similar type terms are to be given their broadest definition and would include a stand or stands joined together for the purpose of being employed in a borehole. Thus, a drill string could include many stands and many hundreds of sections of drill pipe.
As used herein the term “tubular” is to be given its broadest possible meaning and includes drill pipe, casing, riser, coiled tube, composite tube and any similar structures having at least one channel therein that are, or could be used, in the drilling industry. As used herein the term “joint” is to be given its broadest possible meaning and includes all types of devices, systems, methods, structures and components used to connect tubulars together, such as for example, threaded pipe joints and bolted flanges. For drill pipe joints, the joint section typically has a thicker wall than the rest of the drill pipe. As used herein the thickness of the wall of tubular is the thickness of the material between the internal diameter of the tubular and the external diameter of the tubular.
As used herein, unless specified otherwise the term “subsea vehicle” is to be given its broadest possible meaning and would include an manned or unmanned apparatus that that is capable of, or intended for, movement and operation on and under the surface of a body of water, whether the body of water is salt water, fresh water, naturally occurring, manmade, including within a structure, such as a pool of water located above a nuclear reactor, a commercial fish farm, a public aquarium or oceanarium, or a pool of water for testing large equipment, such as NASA's astronaut training pools. Subsea vehicles would include, for example, remotely operated vehicles (“ROVs”), unmanned underwater vehicles (“UUVs”), manned underwater vehicles (“MUVs”), autonomous underwater vehicles (“AUVs”), vehicles that have positive buoyancy, variable buoyancy, neutral buoyancy and negative buoyancy, as well as, tracked, wheeled, or skid vehicles, such as subsea tractors and trenchers, that move along, or are otherwise in contact with the seafloor, or a work object, and underwater robots. As used herein, unless specified otherwise, the term “subsea equipment” is to be given its broadest possible meaning and would all subsea vehicles, as well as, other subsea equipment.
As used herein, unless specified otherwise “high power laser energy” means a laser beam having at least about 1 kW (kilowatt) of power. As used herein, unless specified otherwise “great distances” means at least about 500 m (meter). As used herein the term “substantial loss of power,” “substantial power loss” and similar such phrases, mean a loss of power of more than about 3.0 dB/km (decibel/kilometer) for a selected wavelength. As used herein the term “substantial power transmission” means at least about 50% transmittance.
As used herein, unless specified otherwise, “optical connector”, “fiber optics connector”, “connector” and similar terms should be given their broadest possible meaning and include any component from which a laser beam is or can be propagated, any component into which a laser beam can be propagated, and any component that propagates, receives or both a laser beam in relation to, e.g., free space, (which would include a vacuum, a gas, a liquid, a foam and other non-optical component materials), an optical component, a wave guide, a fiber, and combinations of the forgoing.
As used herein, unless specified otherwise, the terms “ream”, “reaming”, a borehole, or similar such terms, should be given their broadest possible meaning and includes any activity performed on the sides of a borehole, such as, e.g., smoothing, increasing the diameter of the borehole, removing materials from the sides of the borehole, such as e.g., waxes or filter cakes, and under-reaming.
As used herein the terms “decommissioning,” “plugging” and “abandoning” and similar such terms should be given their broadest possible meanings and would include activities relating to permanent abandonment, temporary abandonment, the cutting and removal of casing and other tubulars from a well (above the surface of the earth, below the surface of the earth and both), modification or removal of structures, apparatus, and equipment from a site to return the site to a prescribed condition, the plugback of a borehole to side track or bypass, the modification or removal of structures, apparatus, and equipment that would render such items in a prescribe inoperable condition, the modification or removal of structures, apparatus, and equipment to meet environmental, regulatory, or safety considerations present at the end of such items useful, economical or intended life cycle. Such activities would include for example the removal of onshore, e.g., land based, structures above the earth, below the earth and combinations of these, such as, e.g., the removal of tubulars from within a well in preparation for plugging. The removal of offshore structures above the surface of a body of water, below the surface, and below the seafloor and combinations of these, such as fixed drilling platforms, the removal of conductors, the removal of tubulars from within a well in preparation for plugging, the removal of structures within the earth, such as a section of a conductor that is located below the seafloor and combinations of these.
As used herein the terms “workover,” “completion” and “workover and completion” and similar such terms should be given their broadest possible meanings and would include activities that place at or near the completion of drilling a well, activities that take place at or the near the commencement of production from the well, activities that take place on the well when the well is a producing or operating well, activities that take place to reopen or reenter an abandoned or plugged well or branch of a well, and would also include for example, perforating, cementing, acidizing, fracturing, pressure testing, the removal of well debris, removal of plugs, insertion or replacement of production tubing, forming windows in casing to drill or complete lateral or branch wellbores, cutting and milling operations in general, insertion of screens, stimulating, cleaning, testing, analyzing and other such activities. These terms would further include applying heat, directed energy, preferably in the form of a high power laser beam to heat, melt, soften, activate, vaporize, disengage, desiccate and combinations and variations of these, materials in a well, or other structure, to remove, assist in their removal, cleanout, condition and combinations and variation of these, such materials.
2. Discussion of Related Art
Underwater Activities
Over 70% of the earth's surface is covered with water. Over time there has been a considerable amount of activity on, construction in, and development of the seafloor and the water column between the seafloor and the surface of the water. These underwater endeavors would include, for example: underwater pipe lines for oil, gas, communications, and the transport of materials; offshore hydrocarbon exploration and production; offshore renewable energy production, such as tidal and current based systems; the construction and maintenance of supports extending from the seafloor to at or above the water surface, such as pylons, piles, towers, and other structures, that are used to support bridges, piers, windmills and other structures above the surface of the water; the construction and maintenance of water intakes and outlets for enterprises, such as power plants, factories and municipalities. In future years is it anticipated that such endeavors will increase and that new and more complicated underwater activities and structures will arise. Moreover, as with the case of offshore hydrocarbon exploration and production, these endeavors will be moving to deeper and deeper waters. Thus, for example, today drilling and production of hydrocarbon activities at depths of 5000 ft, 10,000 ft and even greater depths are contemplated and carried out.
By way of general illustration of an example of an underwater activity, in drilling a subsea well an initial borehole is made into the seabed and then subsequent and smaller diameter boreholes are drilled to extend the overall depth of the borehole. Thus, as the overall borehole gets deeper its diameter becomes smaller; resulting in what can be envisioned as a telescoping assembly of holes with the largest diameter hole being at the top of the borehole closest to the surface of the earth, e.g., the seafloor.
Thus, by way of example, the starting phases of a subsea drill process may be explained in general as follows. Once the drilling rig is positioned on the surface of the water over the area where drilling is to take place, an initial borehole is made by drilling a 36″ hole in the earth to a depth of about 200-300 ft. below the seafloor. A 30″ casing is inserted into this initial borehole. This 30″ casing may also be called a conductor. The 30″ conductor may or may not be cemented into place. During this drilling operation a riser is generally not used and the cuttings from the borehole, e.g., the earth and other material removed from the borehole by the drilling activity, are returned to the seafloor. Next, a 26″ diameter borehole is drilled within the 30″ casing, extending the depth of the borehole to about 1,000-1,500 ft. This drilling operation may also be conducted without using a riser. A 20″ casing is then inserted into the 30″ conductor and 26″ borehole. This 20″ casing is cemented into place. The 20″ casing has a wellhead secured to it. (In other operations an additional smaller diameter borehole may be drilled, and a smaller diameter casing inserted into that borehole with the wellhead being secured to that smaller diameter casing.) A BOP is then secured to a riser and lowered by the riser to the sea floor; where the BOP is secured to the wellhead. From this point forward all drilling activity in the borehole takes place through the riser and the BOP.
The BOP, along with other equipment and procedures, is used to control and manage pressures and flows in a well. In general, a BOP is a stack of several mechanical devices that have a connected inner cavity extending through these devices. BOP's can have cavities, e.g., bore diameters ranging from about 4⅙″ to 26¾.″ Tubulars are advanced from the offshore drilling rig down the riser, through the BOP cavity and into the borehole. Returns, e.g., drilling mud and cuttings, are removed from the borehole and transmitted through the BOP cavity, up the riser, and to the offshore drilling rig. The BOP stack typically has an annular preventer, which is an expandable packer that functions like a giant sphincter muscle around a tubular. Some annular preventers may also be used or capable of sealing off the cavity when a tubular is not present. When activated, this packer seals against a tubular that is in the BOP cavity, preventing material from flowing through the annulus formed between the outside diameter of the tubular and the wall of the BOP cavity. The BOP stack also typically has ram preventers. As used herein unless specified otherwise, the term “ram preventer” is to be given its broadest definition and would include any mechanical devices that clamp, grab, hold, cut, sever, crush, or combinations thereof, a tubular within a BOP stack, such as shear rams, blind rams, blind-shear rams, pipe rams, variable rams, variable pipe rams, and casing shear rams.
Regardless of the depth, performing subsea operations can be very difficult, costly, time-consuming and damagers. These obstacles and risks, however, greatly increase, and one could say exponentially increase, as the depth of the water becomes greater, and in particular for deep (e.g., about 1,000 ft), very-deep (e.g., about 5,000 ft) and ultra-deep (e.g., about 10,000 ft and greater) depths. Thus, to minimize the risk to human divers, and for those depths where human divers cannot safely go, and tasks that a human diver could not perform unassisted, subsea equipment has been developed.
Subsea Vehicle Tethers
Such subsea vehicles can be connected to surface support equipment that can be located on vessels, such as a ship, barge, or offshore drilling rig, or located on land, by a tether. In general, and prior to the present inventions, subsea vehicle tethers were limited to providing a way to transmit electrical power and control information from the surface support equipment to the subsea equipment and to obtain images, data, and control information back from the subsea equipment. As the complexity and power demands of subsea vehicles increases, so has the complexity and size of tethers, e.g., diameter, complexity, power capabilities, data capabilities, number of cables, wires, and components. Further as the depth of operations increases, and thus the length of the tether needed increases, the thickness of the electrical power supply wires must similarly increase. A tether for a subsea vehicle could include, by way of example, conductors for transmitting electrical power from the surface to subsea equipment, control throughput for telemetry, either metal wires or optical data fibers, video throughput, either metal wires or optical data fibers, data transmission throughput, either metal wires or optical data fibers, a strength member, buoyancy control material, and outer protective sheathing.
Tether Drag
A significant and long-standing problem with subsea vehicles, and in particular floating subsea vehicles, such as ROVs, is the drag that the tether creates. In order for a subsea vehicle to move, or to remain in a stationary position relative to a work piece, fixed structure or the sea floor when a current is present, the vehicle's thrusters, or other form of motive power, must produce enough thrust to overcome the drag created by the vehicle itself and the tether. In most ROV systems tether drag is a very significant drag factor; and as depth of operation increases tether drag quickly becomes the most significant drag factor; and tether drag can be many multiples greater and on an order of magnitude greater than vehicle drag. Thus, for example, it is reported that for a vehicle working at a depth of 500 ft, in a 1-knot current, and having a vehicle surface area of 10 ft2 and a tether having a diameter 0.75″ (inches) the vehicle drag would be 25.5 lbs (pounds) and the tether drag would be 106.3 lbs. (see R. Christ & R. Wegni, “The ROV Manual”, at p. 32 (2007) (hereinafter Christ, “The ROV Manual”).) Thus, “[w]hen operating at depth (versus at the surface), the greatest influence of current is on the tether cable.” (Christ, “The ROV Manual,” at p. 39.)
As tether length increases tether drag increases. Similarly, as tether diameter increases tether drag increases. Further, as the length of the tether increases, in particular in very deep operations, the diameter of the tether also typically increases, to accommodate the larger electrical power requirements for deeper operations. Thus, a paradigm exists where deep operations require more power and the diameter of the tether is increased to handle the additional power, which in turn further increases the tether drag and requires yet more power.
This paradigm has been described as—“More power drives the cable to become larger, which increases drag, etc. It quickly becomes a vicious design spiral.” (Christ, “The ROV Manual,” at p. 47.) Thus, it was postulated that the perfect ROV would have “a minimal tether diameter (for instance, a single strand of unshielded optical fiber)”; but then noted that this was not obtainable because “the smaller the tether cable diameter, the better—in all respects (except, of course, power delivery).” (Christ, “The ROV Manual,” pp. 18, 29 (emphasis added).) Accordingly, it is believed that until the present inventions, no solution existed to the “vicious design spiral” presented by the tether-drag paradigm.
High Power Laser Beam Conveyance
Prior to the recent breakthroughs at Foro Energy, Inc., it was believed that the transmission of high power laser energy over great distances without substantial loss of power was unobtainable. These breakthroughs in the transmission of high power laser energy, and in particular energy levels greater than about 5 kW, are set forth, in part, in the novel and innovative teachings contained in US patent application publications 2010/0044106, 2010/0044103 and 2010/0215326, and in pending U.S. patent application Ser. Nos. 12/840,978, and 13/210,581; the entire disclosures of each of which are incorporated herein by reference.